CCRI: ENS: Chipyard

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Advanced computing systems lie at the heart of many innovative products, from intelligent earbuds to autonomous vehicles, and these are increasingly built as customized systems-on-a-chip (SoCs). Customized SoCs incorporate a complex mix of general-purpose and customized processing logic, and both software and hardware must be highly tuned to achieve the needed performance and energy efficiency for the target application. Chipyard combines and extends existing community infrastructure components to provide a rich unified framework for research into SoC architecture and implementation, supporting activities ranging from research into new software and new architecture simulation techniques all the way down to test chip fabrication. Chipyard is an integrated SoC design, simulation, and implementation environment to support research and development of specialized computing systems required to meet new application demands in the face of the slowdown in technology scaling. Chipyard is based around the widely used Rocket Chip SoC generator, which includes RISC-V processors, coherent caches, interconnect, and other IP blocks written in the Chisel HDL. Due to the widespread adoption of RISC-V in both academia and industry, there is extensive software support both in upstream open-source software projects as well as increasingly from commercial software providers. Chisel has a growing community, with a series of Chisel Community Conferences and multiple commercial tapeouts of Chisel-based designs. Chipyard IP modules can also be imported from legacy HDLs. RTL designs are converted into a common intermediate representation, FIRRTL, which supports powerful circuit transformations and experimentation with new hardware design tools. For fast, accurate simulation, Chipyard generates FireSim cloud-FPGA-accelerated simulators. FireSim can simulate entire datacenter racks at the RTL level with only a 100X slowdown. FireSim includes performance monitoring, analysis, and debugging tools to allow high observability of design behavior while running at high simulation speed. Chipyard also includes FireMarshal, a software workload management system that allows complete workloads to be easily packaged and recompiled to match an SoC configuration and execution environment. Chipyard integrates the Hammer modular physical design flow, which supports plugins for different tool chains and process technologies, and automates many tapeout steps. Chipyard will also integrate the Berkeley Analog Generator for mixed-signal and analog blocks. Overall, Chipyard provides an integrated environment where a single SoC description can be used to drive conventional open-source or commercial software RTL simulators, or pushed all the way to GDSII layout using industry-standard CAD tools and/or open-source ECAD tools once available. This proposal will fund further development of Chipyard capabilities, managed releases, and community engagement and outreach. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.